Camera Testing – a four way comparison

I’m in very early pre-production for a new TV series.

I was keen to compare the Sony F-55 against the Alexa as this new show will probably feature a lot of on camera flashes, always a problem for rolling shutters like that found on the Alexa.  The global shutter of the F55 should take care of that issue, and the smaller size and apparently very wide colour gamut are also interesting.

I was also interested in testing their 4K RAW recording as well, so I set up a bit of a dynamic range test to compare them.  I also threw a 4K and 2.5K Blackmagic camera into the mix.

The first thing I did was find some skin tone so thanks to my camera department volunteer  Dane Howell for stepping in at the last minute.

The test was done at Panavision Sydney and was thrown together at the last minute so I had to scrape things together.  I would have preferred to do this at daylight colour temperature as most sensors get the most DR at around 5000K. As it was I metered the CT at 2870K.

Lens wise I used the new Panavision V series Primos for all the cameras.  The 40mm for the Alexa, F55 and 4K Blackmagic with the 27mm for the smaller sensored 2.5K bmcc.

I had a grey card along with a skin tone reference card ( both are Fotowand charts from friend Anders at The DOP Shop) plus an X-Rite passport.

Behind dane I set up a piece of poly with a 100w Dedo set to rake along it’s length.  I do this as a way of creating an exposure “ramp” that goes from near white to clipping.  It usually means I can compare the clipping point and it’s easy to pick what is and isn’t clipped.  This clipping point will also shift along the poly as I open the exposure or close it down.

In the deep background I tried to have something that was true black and near black.  Theres another piece of poly down there with some black stripes of tape on it.  It’s barely reflecting back some light and next to is close to true black (in the shade)

I basically assumed the native ISO of the camera was what the manufactured recommend and started off with that as the “Zero” point.  I then went up in half stop increments and down in half stop increments.  So you have + and – 3 stops either side of the manufacture recommended ISO.  You can extrapolate your own ideas about how to expose these cameras from looking and comparing.

So I lit Dane to be 102 Footcandles.  This gives us T 8 @ 800 ISO @ 25 FPS 180 Deg shutter for the Alexa and the BMCC 2.5K

For the F55 the base exposure for zero was T 8 2/3 while the 4K blackmagic was T 5.6.

So if you want access to these files, I’ll need you to leave me an email address in the comments field to invite you with.  I’m using Just Cloud and after uploading them all up there, I’ve now learned that I can’t publicly share a file over 50MB !  There are close to 40GB of files so I’m not uploading them all again to another server !

If you’re worried about spam just substitute the @ for “at”

Make sure you post back your findings too !

DR test